Ring-to-Cage Structural Conversion via Template Effect in a Gold(I) Metallosupramolecular System

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Multinuclear gold(I) complexes offer versatile platforms for constructing complex architectures.
• D-penicillamine (d-H2 pen) serves as a flexible ligand capable of bridging metal centers.
• Understanding structural transformations in coordination systems is key to designing novel materials.

Purpose of the Study:

• To investigate the ring-to-cage structural conversion in gold(I) coordination systems.
• To synthesize and characterize novel multinuclear gold-metal complexes.
• To explore the self-assembly of metallo-supramolecular cages.

Main Methods:

• Reaction of [Au2 Cl2 (dppe)] with d-H2 pen to form a cyclic gold complex.
• Subsequent reactions with copper(II) and nickel(II) salts to induce cage formation.
• Characterization of the resulting multinuclear complexes using spectroscopic and crystallographic techniques.

Main Results:

• A unique cyclic gold(I) complex, [Au4 (dppe)2 (d-pen)2] ([1]), was synthesized.
• Reaction of [1] with Cu(OTf)2 yielded a bicyclic Au4CuII metallocage, [Au4 Cu(dppe)2 (d-pen)2]2+ ([2]2+).
• Reactions with Cu(NO3)2 and Ni(II) salts led to the formation of tricyclic Au8Cu2 and Au8Ni2 metallocages, [Au8 Cu2 (dppe)4 (d-pen)4]4+ ([3]4+) and [Au8 Ni2 (dppe)4 (d-pen)4]4+ ([4]4+), respectively, encapsulating guest molecules.

Conclusions:

• Demonstrated a novel ring-to-cage structural conversion in gold(I) coordination chemistry.
• Successfully synthesized and characterized unprecedented multinuclear gold-metal bicyclic and tricyclic metallocages.
• Highlighted the potential of d-penicillamine as a ligand for constructing complex metallo-supramolecular architectures.